Most social scientists, especially economists, believe that altruists do not exist because they cannot survive exploitation by egoists. An agent-based model demonstrates, however, that altruists can survive natural selection if society comprises four types of individuals: altruists, reciprocal altruists, egoists and reciprocal egoists. These individuals are characterized by different combinations of two phenotypes: general trust and social intelligence. In a society of four types of individuals, coevolution of general trust and social intelligence will emerge. Coevolution constitutes a new mechanism of the emergence of cooperation. If coevolution is strong, altruists will be able to survive and help society evolve into a high-trust and high-growth society. Without altruists, coevolution does not work and society fails to grow. Thus society needs altruists.
商学討究 64 (2/3), 169-194, 2013-12-25